The façade fenestration was strategically specified by the architect. The architectural intent demanded a flush glazed structurally bonded picture frame cassette with an anodised 10mm picture frame trim.

Product Description and Technical Issues

Within the anodised trim a black 20mm borderline frit to face two of the face glass conceals the edge seal of the structural warm edge spacer bar to glass masking the unsightly silicon and butyl sealent, providing a better visual finish whilst eliminating the risk of degradation of the Insulated double glazed units. A 6mm joint between the perimeter edge of the double glazed unit and the anodised trim was factory sealed in- house with down corning black mastic providing a weather tight seal. The corner to corner glass joints have a stepped detail, requiring each face to be individually fritted in gurrantee a satisfactory visual aethetic.

Application of these techmical measures are costly but seen as essential ingredients to a valid warranty, whilst adding to the service life of the overall installation. We always within our budget make provision for facade risk management of such issues. We undestand the impact and knock on effect of defects as a result of their omission and it is our policy to advise the design team of their requirement.

Outside of the cassette trim, a continuous epdm seal around its perimeter creates a continous weather seal and overlap. The vertical and horizontal joint is 20mm allowing in- plane movement of the cassette as a result of possible sway. This solution accomodates 6mm racking per floor.

The insulated double glazed unit is structurally bonded on face four to an anodized trim around the perimeter of the cassette. This approach reduces the visual impact and build up of the perimeter fritting. Alternative profiles within the system range allow for the bonding of both inner and outer pane to the carrier framework.

A Failure Mode and Risk Analysis is always recommended at design stage to ensure that all risks are managed to a satisfactory degree. We often act as consultants in the preparation of such issues at preliminary design stage,

The added value of this type of façade solution and additional control measures required to manage risk was deemed an integral part of the clients corporate payback strategy and whole life cycle approach. Creating each interface detail is our speciality, we enjoy the discussion and making dreams a reality.

Façade Construction

The façade is 17m tall, four floors in height. The mullions span continuous in front of the structure with movement joints located within each spandrel zone. The movement joints accommodate 8mm vertical movement . Each floor is designed to take the dead and live weight of each storey height module. The deflection of the primary structure is designed to suit the movement of the expansion joint. All mullion to transom joints are overlapped allowing water to travel sideways and drain out through a spout.

The facade grid is assembled in stick form with brackets designed to take the dead and live loads at each floor.

The upper 3rd floor glazing spans 5m in height divided into three panes vertically. A secondary steel steel has been introduced to act both as a midspan support to the vertical glazing and a structure to the overhead capped roof 1202 glazing. Typical edge interfaces designed to minimise visual impact. All Perimeter edged cladding designed and manufactured inhouse to agreed autocad setting out to improve buildability on site.

Modernity and Contrast

The vison panels create direct visual contact between the occupant and the urban environment. This create a natural dialogue between internal and external activites, adding visual interest and contrast to the existing façade. Rendered walls hide the activites within the envelope and the coporate strategy was to provide an open type environment.

Passive

The fenestration layout maximises the potential of natural daylight penetration into the deep floor plan. All the glass on face three is soft coated low e, argon filled with swiss warm edge technology to conserve heat gain and minimise linear heat loss around the perimeter of the glazing edges.

The ventialtion approach is mix mode. The mechanical systems is supplimented by natural ventilation through bespoke louvres which are fully integrated with the curtain walling grid.

Aesthetics and Risks

The visual external appearance of the façade was enhanced by using super flat toughened glass. It was a project requirement that Roller wave distortion was minimised to enhance the flatness of the face glass. This can be appreciated when one looks across the river on a bright sunny day.

The risk of NSI Nickel Sulphide Inclusion was managed by (HST) Heat soak testing. This type of defect is always a risk in face glass and it is our policy to incorporate such processes to minimise the risk of occurrence.

Glass thicknesses configuration is designed to accommodate guarding internally. Its nice to look at the full height glazing without the obstructions of a rail or horizontal transom. Point and line loads are taken into consideration as aprt of our glass risk analysis.

Architectural Finishes

The internal finish of the grid is natural anodised forming a strong contrast architecturally to the black fritting externally. Each profile was inspected to ensure that there was no die lines, these often occur during the extrusion process and look like continous line of scratching along its edges. We always use primary billet when carrying out an natural anodised finish.

It is not always possible to manufacture bespoke architectural flashings in natural anodised finish as welding cannot be cleverly masked. All parapets, vertical bay returns, window cills are pressed in 3mm aluminium and coated in-house to a metallic finish, creating a visual parity with its counterpart.

Glazing Workpackage

Projects of this nature can be complex, Working with existing buildings is very demanding. This Glazing package has an extensive technical mix of system products. All manufactured to bespoke sizes, fenestration and finish. These include:

• Fire rated glazing external , 60 min insulation and 60 min integrity to the front face of the building.
• Fire rated internal 30 min insulation, 30 min integrity withih the main entrance area.
• Capped Kawneer roof glazing
• Zone drained curtainwalling.
• Rebated 6000 series doors.
• Structurally bonded cassette system.
• Stainless steel entrance door.
• Projecting Canopy.

All physical interfaces are detailed as bespoke to the site conditions inherent with an existing building. Such interfaces are challenging and require additional workpackage management and a greater understanding of buildability.

At the end the project one always looks back and remineses, projects like this are not for the faint hearted. The lessons learnt on this project and the experiences typify the challenges facing all specialist façade contractors.